In a mixing bowl, combine the ketchup, sriracha sauce, honey, soy sauce, and water. Whisk until well-blended and set aside.
Turn your Instant Pot to the sauté setting. Add the chicken breasts to the pot and sear for about 3-4 minutes on each side, until browned.
Pour the prepared sauce over the seared chicken in the Instant Pot. Make sure the chicken is well-coated.
Seal the Instant Pot lid and set it to pressure cook on high for 10 minutes. Once done, allow for a natural release for about 5 minutes before performing a quick release.
Remove the chicken from the pot and keep it warm. In a small bowl, mix the cornstarch with 1/4 cup of cold water. Turn the Instant Pot back to the sauté setting and stir in the cornstarch mixture. Cook for a few minutes until the sauce thickens to your desired consistency.
Slice the chicken and serve it over cooked rice, drizzled with the thickened sauce. Garnish with chopped scallions for a burst of freshness.